Psychopharmacology Flashcards
LOs for session
- Some understanding of basic psychopharmacology and their application to treatment of different disorders
- Understand the basic presentations, aetiology, epidemiology and intial management of schizophrenia, bipolar disorder, depressino and anxiety
Classic monoamine hypothesis of depression
if the “normal” amount of monoamine neurotransmitter activity becomes reduced, depleted or dysfunctional for some reason, depression may ensue.
Deficient monoamine —> depression
Monoamine receptor hypothesis of depression
Extends the classic monoamine hypothesis of depression.
Deficient activity of monoamine NT’s causes up regulation of postsynaptic monoamine NT receptors. Therefore a smaller proportion of receptors are being activated which is communicated as fewer NTs.
5 classes of antidepressants
TCA= Tricyclic Antidepressant
SSRI= Selective Serotonine Reuptake Inhibitor
SNRI= Serotonine/ Noradrenaline Reuptake Inhibitor
NaSSA= Noradrenaline and Specific Serotinergic Antidepressant
MAOI- MonoAmine Oxidease Inhibitor
What do Tricyclic Antidepressants do
- block Serotonine and Noradrenaline re-uptake
- increasing noradregenergic and serotinergic
What do SSRI’s do?
- block serotonin re-uptake
- increasing serotinergic neurotransmission
What do MAOI’s do?
- Block enzymatic breakdown of noradrenaline, serotonine, dopamine and tyramine
- increasing neurotransmission
What do NaSSAs do
Block pre-synaptic alpha2-adrenoceptors
increasing noradrenergic and serotinergic neurotransmission
Examples and advantages/disadvantages of TCA+related
Of note
- Amitripyline
- Lofepramine
- Trazodone
TCA’s are second line treatment for depression. Strong anti-cholinergic effects therefore:
- Urinary retention
- drowsiness
- blurred vision
- constipation
- dry mouth
Toxic in overdose
Highly cardiotoxic
- Quicker onset than SSRIs?
Examples and advantages/disadvantages of SSRI
Of note
- Fluoxetine
- Sertraline
- Citalopram
- Escitalopram
- Safer in CHD and overdose
- GI upset
- anxiety and agitation
- QT interval prolongation (citalopram)
- sexual dysfunction
- hyponatraemia
- gastric ulcer
Examples and advantages/disadvantages of SNRIs
- Venlafaxine
- Duloxetine
- Non-sedating
- Toxic in overdose
- Sexual dysfunction
- Raise BP at higher doses
Examples and advantages/disadvantages of NaSSA
of note
- mirtazapine
- safer in overdose
- weight gain
- sedation
more sedating at lower doses
Examples and advantages/disadvantages of MAOIs
- Phenelzine
- Tranylcypromine
- Interaction with foods
Others Examples and advantages/disadvantages of
- Agomelatine
- Vortioexetine
Both licensed for major depression only
cautions with tricyclics
- contraindicated in patients with previous heart disease
- can exacerbate schizophrenia
- may exacerbate long QT syndrome
- use with caution in pregnancy and breastfeeding
- may alter blood glucose in T1 and 2 DM
- may precipitate urinary retention so avoid in men with enlarged prostates
- avoid in those with liver damage
All antidepressants are associated with an increased risk of:
- suicidal thoughts and ideation during the first few weeks of treatment
- hyponatraemia due to inappropriate secretion of ADH (particularly in elderly people with SSRIs)
Other indications for antidepressants
- anxiety disorders
- OCD
- panic disorders
- Eating disorders
- Neuropathic pain
- Migraine prophylaxis
- Nocturnal enuresis
cautions with SSRIs
- should be omitted in mania
- used with caution in children and adolescents
- sertraline best for patients wit hischaemic heart disease
cautions with SNRIs
contraindicated in those with a histroy of heart disease and high BP
What are the 4 dopamine pathways in the brain
what does an increase in dopamine cause?
what does a lack of dopamine cause?
- nigrostriatal pathway
- mesolimbic pathway
- mesocortical pathway
- tuberoinfundibular pathway
Increase in dopamine causes positive symptoms for schizophrenia
Decrese causes negative symptoms and cogmnitive symptoms
Examples of 1st gen antipsychotics oral and depot (IM- usually into the glute or thigh)
Oral
- Haloperidol
- Sulpiride
- Pimozide
Depot
- Haloperidol
- Fluphenazine
- Flupentixol
Examples of oral and LAI (long acting injectible///// depot) 2nd gen antipsychotics
Oral
- Amisulpride
- Clozapine
- Lurasidone
LAIs
- Olanzapine
- Risperidone
- Paliperidone
Antipsychotics
First gen
- typically acts on what receptor
- are selective for which of the pathways?
Second gen
- are also known by which name
- act on which receptors
*
first gen
- act predominantly by blocking DOPAMINE D2 receptors
- are not selective for any of the 4 dopamine pathways in the brain, therefore causing a range of side-effects e.g., EPSE, elevated prolactin
Second gen
- atypical antipsychotics
- act on a range of receptors inclulding SEROTONINE receptors
- most distict clinical profiles, particulalry in regard to side-effects
what is the first line antipsychotic of choice
- atypical (2nd gen) antipsychotic which is risperidone
- clozapine is recommended to children and adolescents who have tried 2 other antipsychotics already
- sedatives like lorazepam may be used if there is acute behavioural disturbance in the presentation of schizophrenia but is not first line and wont treat psychosis
